We’ve been working on refining this design for the better part of a year now and are finally happy to make all of the R/D that went into this setup available to the rotary community. For years we battled with cooling related issues with the RX7. Adding high efficiency dual oil coolers really helped the situation but at the end of the day the FD still suffers from problems related to the lack of foresight with the stock water cooling system.

The first issue with the cooling system is the mechanical pump itself. The OEM pumps are (for lack of a better term) garbage with the impeller made from folded sheet metal. Up until this year we've been using the Mazmart RE-medy machined mechanical pumps, however no impeller can be designed for optimal flow at all RPMs... the pump will either under-flow at low RPM's or cavitate at high RPM's. The issue is that the pump, being mechanically connected to the motor, operates regardless of temperature and is forced to spin outside of its optimal range.

So, if you’re overheating but your motor speed drops, you’re now moving less coolant when you need it most. Temperature, load, and RPM all become irrelevant factors with a mechanical pump tied to the crank pulley; it’s just along for the ride. The mechanical pump just does whatever the motor is doing and robs power to do it regardless of how much or little that pump really needs to be working. If we look at optimum pump speed, the mechanical waterpump is either under or overcooling, under or overspinning, or not spinning at all when you need it most (shutdown).

New OEM applications tend to favor electric waterpumps for a number of reasons, one being efficiency (no drag on the motor) and low power consumption (this one takes 8 amps max at full speed, and less as needed), but allows for other possibilities such as continuing to circulate coolant through the motor, radiator, and turbos after shutdown. The controller module we use also has the ability to trigger the fans if the temperature set point is exceeded after ramping the pump speed up. It’s a pretty nice piece of kit and may end up rendering the mechanical waterpump system a thing of the past.

Standard mechanical OEM fitment pumps can be efficient either at high RPM or low RPM, but not both. Our electric water pump is de-coupled from engine speed and is therefore efficient and effective regardless of engine speed.

Cooling on demand

Electric water pump operation is based on coolant temperature, and the controller can modulate the speed of the pump in real time based on cooling requirements.

Controller temperature settings are customizable

The fans can be activated by the pump controller to increase cooling capabilities if the controller finds that the temperature is continuing to increase so that control of the water pump and fan operation is optimized to prevent overheating.

Belt slip on the mechanical water pump pulley is now a thing of the past!

The end result of the system is the ability to activate maximum cooling even at low RPM, or after key-off.

Free up power and throttle response

Saves horsepower by removing the resistance of the mechanical water pump on the engine. 2-7hp depending on RPM.

Contoured fluid path to drastically reduce turbulence and vortices forming in the water pump housing with the mechanical water pump removed

Months of flow testing and revisions to create bowled output to fluid passage; this reduces turbulence by preventing quickly moving coolant from hitting a flat wall rather than smoothly directed towards the coolant inlet. The smooth flow contour aims to achieve as close to truly laminar flow as design constraints allow. Less turbulence means less flow restrictions and therefore more efficient and effective cooling.

The plate has a C-ring that seats in the same beveled surface that the mechanical water pump blades do, forcing the vast majority of the coolant through the flow path rather than allowing it to whirl around, causing turbulence

Located in lowest possible orientation to aid in reducing trapped air, essential for operation of the pump

Electric water pumps are significantly more sensitive to air pockets than mechanical water pumps, so properly bleeding the cooling system is a must. The pump is also installed as low in the engine bay as possible to help make this easier.

Having an electric water pump allows you to bleed the coolant system easier; with a 12V power source, you can manually circulate coolant through the engine without needing the car to be on. (With a manual pump we found the bleeding procedure to be a multi-day process if done thoroughly.)

Optionally available with high quality Samco silicone hose upgrade made to spec

Thermosensor included with the kit

Correctly sized belt is included to allow for deletion of the water pump and pulley from the system